The complete opposite of what scientists thought.

.

From publication today in Cell

Quoting from the Sciencealert report:

“German scientists have discovered that our brains are actively taking in sugar from the blood stream, overturning the long-held assumption that this was a purely passive process.

.

Even more surprising, they also found that it’s not our neurons that are responsible for absorbing all that sugar – it’s our glial cells, which make up 90 percent of the brain’s total cells, and . . .

.

Not only does the find go against conventional wisdom on how our brains respond to sugar intake, it also shows how cells other than our neurons can actively play a role in controlling our behaviour.

.

Astrocytes – which are a specialised form of glial cell that outnumber neuronsmore than fivefold – have long been thought of as little more than ‘support cells’, helping to maintain the blood-brain barrier, carry nutrients to the nervous tissue, and play a role in brain and spinal cord repair.

.

But we now have evidence that they also play a role in human feeding behaviours, with researchers finding that their ability to sense and actively take in sugar is regulating the kinds of appetite-related signals that our neurons send out to the rest of the body.

.

And we’re not talking about a little bit of sugar here: the human brain experiences the highest level of sugar consumption out of every organ in the body.

.

“Our results showed for the first time that essential metabolic and behavioural processes are not regulated via neuronal cells alone, and that other cell types in the brain, such as astrocytes, play a crucial role,” explains study leader Matthias Tschöp from the Technical University of Munich.

.

“This represents a paradigm shift and could help explain why it has been so difficult to find sufficiently efficient and safe medicines for diabetes and obesity until now.”

.

Tschöp and his team decided to investigate how the brain decides to take in sugar from the blood – and how much – because this is directly related to our feelings of hunger.

.

. . .The team used positron emission tomography (PET) scans to observe how insulin receptors act on the surface of the brain’s astrocytes. Insulin is a hormone produced by the pancreas to allow the body to use or store sugar (in the form of glucose) from carbohydrates in the food we eat.

.

They found that if these receptors were missing on certain astrocytes, it would result in less activity in the neurons that are responsible for curbing food uptake, called proopiomelanocortin neurons.

.

Not only that, but they found that astrocytes missing insulin receptors actually became less efficient over time in transporting glucose into the brain – particularly in a region of the hypothalamus that sends out signals that you’re full, or satiated.

.

So it looks like glial cells, not the neurons, are the true ‘gate-keepers’ for how much sugar our brains absorb, and we now know that sugar has such a powerful influence on them, they’re seeking out sugar, rather than just passively absorbing it.

.

A better understanding of how this works could change everything about how we treat obesity in the future.”